Method for reducing welding hollows of LTCC substrate and metal base plate and LTCC substrate structure

Abstract

The invention discloses a method for reducing welding hollows of an LTCC substrate and a metal base plate. The method comprises the following steps: presetting criss-cross resistance welding grid lines on a metalization layer of the surface of the substrate, and then welding the LTCC substrate and the metal base plate by adopting welding paste. As the grid lines are printed on the metalization layer of the welding surface of the LTCC substrate, discharge of fluxes and gas can be increased during welding of the LTCC substrate and the metal base plate, the formation of the hollows is reduced, and the voidage is reduced. As the grid lines are printed on the metalization layer of the welding surface of the LTCC substrate, more fluxes and gas can be discharged during welding, the accumulation of fluxes and gas is prevented, the welding area is increased, and the area of the biggest hollow is reduced. The design of multi-layer substrates and high-density grounding through holes does not need to be changed, many times of printing alignment for thickening of the rectangular-block metalization layer is avoided, and the grid lines are directly printed on the large-area metalization layer of the substrate. The printing is simple, the grid lines are clear and reliable, and the discharge channel of the fluxes can be ensured.

Description

technical field [0001] The invention relates to a method for reducing welding voids between an LTCC substrate and a metal bottom plate and a novel LTCC substrate obtained by the method. Background technique [0002] With the development of microelectronics technology, low-temperature co-fired ceramics (LTCC) for multilayer circuit wiring have been more and more widely used in the miniaturization and high-density integration of modules or systems, especially in microwave / radio frequency, LTCC It has unique advantages as a substrate for transceiver components. In use, LTCC ceramic substrates are often welded to heat sinks or metal shells (both called metal bottom plates). At present, the welding of the LTCC ceramic substrate and the metal base plate is generally sintered on the surface of the substrate with a weldable thick-film metallization layer (soldering layer), and then printed or coated with tin solder paste (such as low-temperature solder paste Sn62Pb36Ag2, medium-te...

AI Technical Summary

Problems solved by technology

If the spacing between the bulk metallization areas is too large, although it is conducive to the escape of flux and gas during welding, the too wide spacing reduces the welding area and grounding area, which affects the welding strength and grounding performance

If the spacing between the block metallized areas is too small, there will be alignment problems when the metallized areas are thickened (two or more repeated printings), it is difficult to control the spacing accuracy, and adjacent blocks are prone to appear during welding The bridging of solder between metallized areas blocks the escape channels of organics and gases, and the discharge of organics and gases (i.e., the reduction of voids) is affected

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